Problem: $ \left(\dfrac{81}{16}\right)^{\frac{1}{2}}$
Answer: Figure out what goes in the blank: $\Big(? \Big)^{2}=\dfrac{81}{16}$ Figure out what goes in the blank: $\Big({\dfrac{9}{4}}\Big)^{2}=\dfrac{81}{16}$ So $\left(\dfrac{81}{16}\right)^{\frac{1}{2}}=\dfrac{9}{4}$